Los Angeles -LRB- CNN -RRB- -- Federal authorities on Friday arrested a man on a weapons charge as he was being released from a Los Angeles County jail a day after he pleaded guilty in the 2011 brutal beating of a Giants fan at Dodgers Stadium and received credit for time served .

Agents from the Bureau of Alcohol , Tobacco , Firearms and Explosives took Marvin Norwood , 33 , into custody Friday morning on a federal weapons charge as the Los Angeles County sheriff released him .

Norwood was sentenced Thursday to four years in prison immediately after pleading guilty to felony assault by means likely to produce great bodily injury . He was released Friday with credit for having been held in jail in the case for more than two years .

A co-defendant , Louie Sanchez , 31 , also pleaded guilty Thursday to felony mayhem and was sentenced to eight years in prison .

In exchange for the guilty pleas , prosecutors dropped other felony charges .

Prosecutors say the two men attacked Bryan Stow in the Dodgers ' stadium parking lot after the opening day game on March 31 , 2011 , when the team played the San Francisco Giants .

Stow is a Giants fan .

Stow , a paramedic from Santa Cruz , California , went into a coma as a result of the beating and , after returning to consciousness , is still struggling with a severe brain injury .

Stow , now 45 , is disabled and unable to care for himself , his father , David , told the court Thursday .

Stow is also a father of two .

Norwood faces a charge of being a felon in possession of firearms , and the charge relates to firearms that authorities allegedly found in Norwood 's home in Rialto , California , during their investigation into Stow 's beating , according to a spokesman for the U.S. attorney 's office in Los Angeles and to an FBI affidavit .

Sanchez also faces the same federal charge , said Thom Mrozek , spokesman for federal prosecutors in Los Angeles .

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Marvin Norwood , 33 , faces a federal charge of being a felon in possession of firearms

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Feds arrest Norwood as he 's being released from a Los Angeles County jail

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He pleaded guilty in a 2011 brutal beating of a Giants fan at Dodgers Stadium

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He was released because he was given credit for time while being held in jail